Comments on: Data Coverage in Cowtan and Wayhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/
by Steve McIntyreThu, 08 Dec 2016 12:56:06 +0000hourly1http://wordpress.com/By: The Lewandowsky Smooth | ManicBeancounterhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-708395
Thu, 07 Aug 2014 22:57:19 +0000http://climateaudit.org/?p=18635#comment-708395[…] the authors first removed some of the HADCRUT4 data, stating reasons for doing so. In total Roman M found it was just 3.34% of the filled-in grid cells, but was strongly biased towards the poles. […]
]]>By: RomanMhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454241
Wed, 04 Dec 2013 17:28:56 +0000http://climateaudit.org/?p=18635#comment-454241Thanks for the clarification.

Did you consider separating the data by month and using 12 different variograms rather than one? It seems to me that that might better accomodate the annual cyclicity in the variability of the temperature.

]]>By: Robert Wayhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454236
Wed, 04 Dec 2013 16:40:13 +0000http://climateaudit.org/?p=18635#comment-454236I consulted with Kevin (Cowtan) to ensure that my response was on the mark. We have tested a million things so it was important to ensure it was coherent.

We used one variogram covering all months but three different methods have been tested.

Time correlation or covariance between different pairs of cells, and mean squared difference as a function of distance.

The latter approach was selected because it gives the most conservative kriging ranges. However, tests on the three methods showed that the resulting temperature series were largely insensitive to the method.

]]>By: RomanMhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454227
Wed, 04 Dec 2013 15:12:08 +0000http://climateaudit.org/?p=18635#comment-454227I have a question about the kriging methods used in the paper. You state that:

The semivariogram of the observed data is determined by calculating the square of the difference between every pair of observed temperatures in every month of the data and averaging the results in 300km radial bins.

It is a bit unclear to me as what exactly is being done here. Are you saying that the semivariogram is being calculated and used separately for each month or are you calculating a single semivariogram which can then be used for all of the months? The latter might be part of an approach of viewing the situation as a space-time kriging problem.

]]>By: HaroldWhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454135
Wed, 04 Dec 2013 05:57:11 +0000http://climateaudit.org/?p=18635#comment-454135Robert,
Thanks for making the paper freely available.
]]>By: david eisenstadthttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454096
Wed, 04 Dec 2013 01:08:35 +0000http://climateaudit.org/?p=18635#comment-454096robert I just want to thank you for taking the time and energy to engage with the community here. Im sure its not fun reading some of the more intemperate posts, but I hope you are aware of how much many of us appreciate your presence here. thanks.
]]>By: Robert Wayhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454091
Wed, 04 Dec 2013 00:21:14 +0000http://climateaudit.org/?p=18635#comment-454091Hello All,
Just thought you would be interested in knowing that the Cowtan and Way paper is now openly available at QJRMS.

]]>By: RomanMhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-454089
Wed, 04 Dec 2013 00:01:08 +0000http://climateaudit.org/?p=18635#comment-454089It is pretty obvious that that you do not seem to have much experience with the concept of what constitutes a “publication” in a scientific journal.

This post raises some questions for discussion as one might do in a seminar. The purpose of a seminar is to understand a topic and to gain insight and new ideas from the discussion that follows. The seminar would rarely lead directly to sufficient conclusions that would become a completed paper meriting publication as an article in a scientific journal. The value of the post is often the individual knowledge taken away by the participants themselves.

Your comment is appreciated for the value which it has added to the discussion.

]]>By: tumetuestumefaisdubien1https://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-452554
Fri, 29 Nov 2013 01:48:03 +0000http://climateaudit.org/?p=18635#comment-452554I was looking into the issue of where from the C&W actually got their rising trend for the hockeyschtickle divergence since 2005 from Hadcrut, because their result is quite very inconsistent with the (almost already significantly rising) global seaice trends and RSS polar LTT anomaly because I couldn’t believe they would just sraighforwardly fabricated it.
What I’ve found is maybe interesting.
I compared the RSS and UAH polar LTT data and it very much looks that only where one finds a relatively prominent rising trend with satellite data is actually Antarctica LTT land in UAH. Arctica is flat or descending in both RSS and UAH since the 2005. See:
fulsize here. I was also looking into the landstation surface records in GHCN to check whether their trends agree with UAH LTT and the result is inconclusive – sometimes yes, but very often not – for example Amundsen-Scott, Belgrano, Butler island, Byrd, Casey, Davis, Dawson, Dumont D’Urvi, Lettau, Mawson, Mirnyj, Neumayer, Novolazarevsk, Rothera point, Syowa or Vostok – an almost representative sample of the Antarctica surfacestations – quite not (if someone is interested here I´ve ziped graphs) which puts already the UAH Antarctica at very least the LTT-polarland dataset quite into question.
So I was wondering whether there was not an extrapolation of land UAH-LTT trend into the circumpolar ocean seaice strip in the C&W no data exercise, because I quite can’t find any other possible source for their very dubious and most probably spurious global trend – and especially when one looks at the recent literally freezing global seaice trends (-which almost surely will make this monthly global maximum highest since 2003 and likely even since 1999 and most likely very simmilar it will be with the whole yearly average – see e.g. here, here, or here – I note for record that I extrapolated the last two missing daily values for November to get monthly average) it is really implausible – water simply does not freeze upon warming.
]]>By: TAGhttps://climateaudit.org/2013/11/23/data-coverage-in-cowtan-and-way/#comment-452211
Wed, 27 Nov 2013 20:30:10 +0000http://climateaudit.org/?p=18635#comment-452211A common road sign in cold countries is one that indicates that bridge surfaces become icy before normal road surfaces. Drivers must be aware of black ice on bridges when other portions of the road have no ice. Bridges are exposed to cold air both below and above. Normal road surfaces are not. Ice covered oceans could be different from ice covered land for a similar reason
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